Portable wireless terminals such as cell phones are being enhanced increasingly in multifunctionality; for example, they have come to be provided with not only the telephone function, the e-mail function, and the function of accessing the Internal etc. but also the short-range wireless communication function, the wireless LAN function, the GPS function, the TV viewing function, the IC card settlement function, etc. With such enhancement in multifunctionality, the number of antennas incorporated in portable wireless terminals is increasing and degradation of the antenna performance due to coupling between plural antenna elements is now a serious problem.
On the other hand, from the viewpoints of design performance and portability, portable wireless terminals are now desired to be further miniaturized and increased in integration density. To maintain good antenna characteristics while miniaturizing a terminal, it is necessary to make various improvements in the arrangement of antenna elements and the coupling between the antenna elements. Furthermore, a high-performance antenna system is desired in which the numbers of feeding paths and antenna elements are made as small as possible and a proper measure against degradation due to coupling is taken.
As disclosed in, for example, Patent Literature 1 and Non-patent Literature 1, portable wireless terminals are known which solve the problem of coupling between an elements. These portable wireless terminals are configured so as to realize low correlation between antennas by inserting a connection circuit so that it connects feeding portions of array antenna elements and thereby canceling out mutual coupling impedance between the antennas.